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Featured researches published by Ryo Nemoto.


international solid state circuits conference | 2010

A 12.3-mW 12.5-Gb/s Complete Transceiver in 65-nm CMOS Process

Koji Fukuda; Hiroki Yamashita; Goichi Ono; Ryo Nemoto; Eiichi Suzuki; Noboru Masuda; Takashi Takemoto; Fumio Yuki; Tatsuya Saito

A 12.3-mW 12.5-Gb/s complete transceiver based on the 65-nm standard digital CMOS process was developed. The chip includes a clock-and-data-recovery (CDR) device, a multiplexer/demultiplexer (MUX/DEMUX), and a global clock-distribution network. To reduce power consumption, a low-swing voltage-mode driver with pulse-current boosting and an LC resonant-clock distribution with distributed on-chip inductors are used in the transmitter, while a symbol-rate phase detector (SPD) using a three-stage sense amplifier and phase-rotating phase-locked loop (PLL) with variable delay are used in the receiver. The transceiver operates at a bit error rate (BER) of 10-12 or less through a 20-cm test board with total attenuation of -12.1 dB while consuming power of 0.98 mW/(Gb/s) per transceiver.


international solid-state circuits conference | 2010

A 12.3mW 12.5Gb/s complete transceiver in 65nm CMOS

Koji Fukuda; Hiroki Yamashita; Goichi Ono; Ryo Nemoto; Eiichi Suzuki; Takashi Takemoto; Fumio Yuki; Tatsuya Saito

For the people involved with multi-Gb/s chip-to-chip serial links, reducing power dissipation per Gb/s to less than 1mW/(Gb/s) (i.e., 1pJ/b) has been a long-held goal. Several years ago, the power dissipation of these links was in the range of about 10 to 20mW/(Gb/s). In 2007, Poulton et al. developed a 14mW 6.25Gb/s transceiver with power efficiency of 2.2mW/(Gb/s) [1]. Thereafter, there were some efforts aiming to reduce power of each building block in a transceiver [2, 3]. This paper presents a 12.3mW 12.5Gb/s complete transceiver (including CDR, MUX/DEMUX, and global clock distribution)in 65nm CMOS with power efficiency of 0.98mW/(Gb/s). To achieve low power, a resonant-clock distribution with distributed on-chip inductors and a low-swing voltage-mode driver with pulse-current boosting are used in the transmitter, while a symbol-rate comparator/phase detector using 4-stage sense amplifier and phase-rotating PLL with variable delay are used in the receiver.


international solid-state circuits conference | 2008

An 8Gb/s Transceiver with 3×-Oversampling 2-Threshold Eye-Tracking CDR Circuit for -36.8dB-loss Backplane

Koji Fukuda; Hiroki Yamashita; Fumio Yuki; Masayoshi Yagyu; Ryo Nemoto; Takashi Takemoto; Tatsuya Saito; Norio Chujo; Keiichi Yamamoto; Hisaaki Kanai; Atsuhiro Hayashi

IT systems such as servers and routers need high-speed lower- power area-efficient chip-to-chip interconnections through backplane boards. These interconnections must overcome signal degradation due to the large insertion loss of low-cost boards. In this work, a 90nm CMOS 8Gb/s transceiver is developed. A TX 5- tap FFE, an RX analog equalizer, and a 2-tap DFE combined with a 2-threshold eye-tracking CDR achieve a BER of less than 10-12 through a 160cm backplane board with -36.8dB loss at 4GHz and a transceiver power consumption of 232mW (transmission efficiency of 1.2Gb/sxdB/mW).


international solid-state circuits conference | 2005

A wireless biosensing chip for DNA detection

Yoshiaki Yazawa; Tadashi Oonishi; Keiki Watanabe; Ryo Nemoto; Masao Kamahori; Takehiko Hasebe; Y. Akamatsu

A wireless sensing chip for biological assay is fully operational in a sample solution. The IC monolithically integrates a biological sensor, an RF communication circuit, and a coupling coil on a 2.5/spl times/2.5 mm/sup 2/ chip in 0.35 /spl mu/m CMOS technology. Detection of single nucleotide polymorphism (SNP) in DNA is successfully carried out by the chip.


Japanese Journal of Applied Physics | 2010

Radio Frequency Identification Sensor Chips with Anticollision Algorithm for Simultaneous Detection of Multiple DNA Targets

Yoshiaki Yazawa; Tadashi Oonishi; Kazuki Watanabe; Ryo Nemoto; Akiko Shiratori

A newly developed DNA measurement method for multiple single nucleotide polymorphism (SNP) typing using a radio-frequency identification (RFID) sensor chip was demonstrated. The RFID sensor chip monolithically integrates a sensor, amplifier, analog-to-digital converter (ADC), and a passive wireless communication interface for receiving commands and transmitting data on a 2.5×2.5 mm2 silicon chip. For the simultaneous multitarget measurement, anticollision control and peak-power suppression are essential. To assign a unique identification number (UID) for the identification of multiple sensor chips, a reproducible random number generator circuit (RRG) was designed and installed on the chip. Peak-power consumption was reduced to 1018 µW by a clock gating of functional circuit blocks. Multiple SNP typing was carried out by simultaneously operating five RFID sensor chips (four with photosensors and one with a temperature sensor). The target DNA was captured on the sensor chips, and SNPs were detected by observing bioluminescence. Finally, the observed data were wirelessly transmitted to the reader.


IEEE Journal of Solid-state Circuits | 2009

A 10-Gb/s Receiver With Track-and-Hold-Type Linear Phase Detector and Charge-Redistribution First-Order

Koji Fukuda; Hiroki Yamashita; Fumio Yuki; Goichi Ono; Ryo Nemoto; Eiichi Suzuki; Takashi Takemoto; Masashi Kono; Tatsuya Saito

A 10 Gb/s receiver with a digital CDR uses a track-and-hold-type linear phase detector (LPD) and charge-redistribution first-order ΔΣ modulator. It has low quantization error and high loop bandwidth due to the use of the LPD and maintains the advantages of a digital CDR such as low power consumption, small area, fast locking time, and low-jitter recovery clock because no internal VCO is needed. The CDR tracking bandwidth is 20 MHz and high-frequency jitter tolerance is 0.42 UIpp at 10-12 BER. Power consumption of LPD is 2.6 mW while the entire receiver consumes 65 mW.


international solid-state circuits conference | 2009

\Delta\Sigma

Koji Fukuda; Hiroki Yamashita; Fumio Yuki; Goichi Ono; Ryo Nemoto; Eiichi Suzuki; Takashi Takemoto; Tatsuya Saito

A CDR circuit and a phase detector are the key building blocks of high-speed interconnect systems. Today, most CDR circuits use bang-bang phase detectors. These phse detectors have several advantages, including low power consumption, a simple circuit structure, and compatibility with digital circuits [1,2]. However, bang-bang phase detectors have the intrinsic drawback of large quantization noise. Therefore, the CDR loop bandwidth must be relatively low to mitigate the effect of the quantization noise by time averaging. In particular, digital CDRs operated in a Δ-modulation loop are susceptible to quantization noise. On the other hand, linear phase detectors (LPDs) do not exhibit quantization noise and therefore by using them one can potentially increase the CDR bandwidth to achieve improved jitter tolerance. However, conventional LPDs, such as the Hogge phase detector, which detect the phase difference as a pulse width, cannot be easily incorporated in a digital CDR [3]. In this paper, a 10Gb/s receiver is described that is equipped with a track-and-hold-type LPD as well as a charge-redistribution ΔΣ modulator for incorporation in a digital CDR. The 10Gb/s receiver exhibited low quantization errors and high loop bandwidth that are due to the use of a linear phase detector while it maintains the advantages of a digital CDR circuit, such as low power consumption, small area occupation, fast locking time, and a low-jitter recovered clock because an internal VCO is not needed. The tracking bandwidth of the CDR circuit is about 20MHz, and the power consumption of the receiver is 65mW


international solid-state circuits conference | 2011

Modulator in 90-nm CMOS

Goichi Ono; Keiki Watanabe; Takashi Muto; Hiroki Yamashita; Koji Fukuda; Noboru Masuda; Ryo Nemoto; Eiichi Suzuki; Takashi Takemoto; Fumio Yuki; Masayoshi Yagyu; Hidehiro Toyoda; Masashi Kono; Akihiro Kambe; Seiichi Umai; Tatsuya Saito; Shinji Nishimura


Archive | 2005

10Gb/s receiver with track-and-hold-type linear phase detector and charge-redistribution 1 st -order ΔΣ modulator

Ryo Nemoto; Tadashi Oonishi; Kazuki Watanabe; Yoshiaki Yazawa; Yasushi Goto; Hiroshi Yoshigi


Archive | 2005

A 10:4 MUX and 4:10 DEMUX Gearbox LSI for 100-Gigabit Ethernet Link

Kazuki Watanabe; Ryo Nemoto; Yoshiaki Yazawa

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